Pattern mechanism for knitting machines



April 19, 1966 R. M. JANDA ETAL PATTERN MECHANISM FOR KNITTING MACHINES Filed April 12, 1963 3 Sheets-Sheet 1 INVENTOR. Richard M. Jan d0 Robert L. Sterner April 19, 1966 R. M. JANDA ETAL PATTERN MECHANISM FOR KNITTING MACHINES 3 Sheets-Sheet 2 Filed April 12, 1963 m T. m V m Richard M. Janaa Robert L. Sterner ATTORNEY.

A ril 19, 1966 R. M. JANDA ETAL 3,246,487

PATTERN MECHANISM FOR KNITTING MACHINES Filed April 12, 1963 3 Sheets-Sheet 5 III FlE- 5 lN VENTOR. Richard M. Janda BY Robert Sterner ATTORNEY.

United States Patent C) 3,246,487 PATTERN MECHANISM FOR KNITTING MACHINES Richard M. Janda, Mount Penn, Reading, and Robert L.

Sterner, West Reading, Pan, assignors to Textile Machine Works, Wyomissing, Pa, a corporation of Pennsylvania Filed Apr. 12, 1963, Ser. No. 272,784 9 Claims. (Cl. 66--50) This invention relates to improvements in circular knitting machines and more particularly to needle selecting and operating means of such machines for forming design stitch patterns, having bothv ornamental and run-resisting characteristics, in tubular stockings knitted thereon.

In circular knitting machines for knitting ladies seamless stockings, means are provided for feeding yarns to and for operating the needles during rotary operation to form run-down portions of the stockings and during reciprocatory operation to form heel and toe portions of the stockings. The machines are also provided with means for selectively controlling the operation of the needles to form different patterns of design stitches in the run-down portions of the stockings, the means for this purpose comprising pattern jacks having up to twentysix pattern butt levels, and pattern devices including selector levers, one for acting on the jack butts at each level, and a trick drum having a controlling butt pattern for operating eachof the selector levers.

Commonly, each of the different design stitch patterns to be formed require a jack butt pattern which is arranged within a group of adjacent butt levels and acted on by a group of selector levers in the corresponding levels. All of the selector levers of each of the different groups are simultaneously moved between active and inactive positions by control levers which are operated in the same desired sequence by connections controlled and operated from the cam drum during each stocking knitting cycle of the machine. Due to limitations within the machine the number of levers available for controlling the different groups of selector levers is limited to four, and in some instances each lever may be used to control a group of selector levers to form a different design pattern in difv ferent portions of the stockings. However, where two of the control levers are required to control portions of the same group of selector levers in forming the design pattern in one of the portions of the stocking, for instance in the leg, where one half of the pattern is set up in one half of the group of jack butt levels in one half of the needle cylinder and the other half of the pattern is set up in the other half of the group of jack butt levels in the other half of the cylinder, the control lever for the group of selector levers controlling the formation of one of the other design stitch patterns must be eliminated in order to remain within the limit of the available control levers.

When a variation in the design pattern is desired and such variation may be arranged within the same groups of jack butt levels it is only necessary to provide new pattern jacks and tricks in the trick drum having the required butt pattern to operate the same groups of selector levers. However, where the variation in the design pattern also requires a different number of butt levels, in addition to the changes to the pattern jacks and trick drum pattern, it is also necessary to provide different control levers for the different groups of selector levers required by the new pattern. While the cost of making such changes is usually not objectionable in mills where machines are operated to produce stockings having the j 3,246,487 Patented, Apr. I8, 1966 intervals, such costs become prohibitive in mills making stitch patterns in tubular knitted stockings, which means is capable of varying the design stitch pattterns formed in stockings knitted in successive operating cycles of the machine.

A further object is the provision of means in a circular knitting machine for forming design stitch patterns. in tubular stocking fabrics knit in successive stocking knitting cycles of the machine, which means includes pattern jacks associated with the needles of the machine and having a different butt pattern for each of the design stitch patterns to be formed, and a different group of selector levers for acting on each of the different butt patterns on the jacks, said means further includes control means for individually controlling the operation of the selector levers, the control means acting at times to change the operation of the selector levers within the different groups and at other times acting to change the order of operation of the different groups to form different arrangements of the design stitch patterns in the stockings knitted in a plurality of successive knitting cycles.

A still further object is the provision of pattern means for controlling the operation of a knitting machinethrough complete stocking knitting cycles, the pattern means including a first pattern device which is operated through a complete operating cycle during each stocking knitting cycle, a second pattern device which is operated through a plurality of complete operating cycles during each stocking knitting cycle, and a third pattern device which is operated through a complete operating cycle during a plurality of stocking knitting cycles.

With these and other objects in view, which will become apparent from the following detailed description of the illustrative and practical embodiment of the invention shown in the accompanying drawings, the invention comprises the novel elements, features of construction and combination of parts in cooperative relationship as hereinafter more particularly pointed out in the claims.

In the drawings:

FIG. 1 is a top plan view of a portion of a circular knitting machine, for knitting tubular stocking fabrics, having jack selecting and controlling mechanism in accordance with the instant invention applied thereto;

FIG. 2 is a view of the mechanism of FIG. 1 with certain parts being omitted in order to show other operating parts of the mechanism; 7

FIG. 3 is a cross-sectional view taken on the line and in the direction of the arrows 3-3 of FIG. 1;

FIG. 4 is an elevational view of a portion of the mechanism of FIG. 1 taken in the direction of the arrow 4;

FIG. 5 is a view of the mechanism of FIG. 1 with certain parts being omitted and other parts being shown in cross section in order to illustrate further operating parts of the mechanism;

FIG. 6 is a view taken transversely through the machine showing certain of the control means for the mechanism of FIG. 1; 7

FIG. 7 is a view taken in the direction of the arrow 7-7 of FIG. 6; and

FIG. 8 is a schematic vie-w of-the, pattern, jacks and different arrangements ofpattrn butts for forming the different design stitch patterns in the stocking fabrics.

Referring to FIGS. 1 and 3 of the drawings there is shown a portion of a conventional circular knitting machine adapted for both rotary and reciprocatory operation, including a cylinder having slots 11 for slidably mounting needles 12, and means (not shown) for feeding yarns to the needles and for operating the needles to knit the yarns into tubular fabrics such as for womens seamless stockings. The machine is also provided with pattern means for controlling the operation of the needles to form design stitch patterns in different portions of the stocking fabrics, the pattern means including an intermediate jack 13 and a pattern jack 14 associated with each needle and means for selectively operating the pattern jacks. While only the jack selecting means for controlling the needles at a single knitting station of the machine is shown and described herein, it is to be understood that in machines having more than one knitting station, similar selecting means is adaptable to control the needles at each of the stations.

The pattern jacks 14 are of the common rocking type each having a butt 15 for engagement with a cam (not shown) to raise the jack and its associated needle during the formation of design stitch patterns in dilferent portions of the stocking fabrics, and breakable pattern butts 16. The pattern butts 16 are arranged on the jacks at a plurality of levels, up to 26 or more, and the butts in each level are acted on by a selector lever pivoted on a vertical pin 18 and having a projecting nose portion 19 adapted to read a trick butt pattern at a corresponding level on a trick drum 21. The trick drum 21 is provided with ratchet teeth 22 adapted to be acted on by a pawl 25 which is operated by means hereinafter set forth to advance the trick drum in synchronism with the rotation of the cylinder 10.

The pawl 25 is pivotally mounted on one arm 26 of a bell crank 27 which is pivotally carried on a stud or bolt 30 secured on a plate 31 forming a part of the framework of the machine (FIGS. 4 and 5). A second arm 32 of the bell crank 27 is connected by a rod 35 to one arm 36 of a second pivoted bell crank 37. A second arm 40 of the bell crank 37 is connected by a link or rod 41 to an arm 42 of a lever 45 mounted for rocking movement on a shaft 46 supported in brackets, one of which is shown at 47, carried on frame members 56) of the machine (FIG. 6). Lever 45 is provided with a second arm 51 having a rotatable roller 52 adapted to engage a cam 55 on a shaft 56 mounted for rotation in the bracket 47. A spring 57 connected between the end of arm 51 and the frame member biases the lever and arm counterclockwise to normally maintain the roller 52 in engagement with the cam. The shaft 56 is driven by gearing (not shown) to make one rotation during each rotation of the cylinder 10 and the cam is provided with two high points 60 which act on the lever 45 and the connecting linkage to operate the pawl 25 through two movements to advance the trick drum 21 two teeth for each rotation of the cam.

Desirably, the movement of the trick drum 21is arrested to interrupt the formation of a design pattern when it is being formed in the leg portion of the stocking at the start of reciprocating knitting for the heel and the trick drum is again restarted at the completion of the heel to continue the design stitch pattern in the foot of the stocking. For this purpose, the lever 45 is arrested in a position to which it is moved by one or the other of the high points 60 of the cams 55 by engagement of a stud 61 with the upper surface of a third arm 62 of the lever 45. The stud 61 is adjustably carried in a finger 65 projecting at right angles from one arm 66 of a lever 67. The lever 67, which is pivoted at 70 on a bracket 71 secured to the bracket 47, is provided with a second arm 72 having a pin 75 adapted to be received in an elongated slot '76 in a block 77. The block 77 is connected to one end of a -Bowden wire 78 which is guided for movement in a hollow stud 80 adjustably carried in an arm 81 of the bracket 71. A compression spring 81 surrounding the Bowden wire 78 between the block 77 and the end of the stud 80 tends to move the block away from the stud and a tension spring 85 connected between the block and the arm 66 of lever 67 biases the lever counterclockwise as viewed in FIG. 6 to normally maintain the pin 75 in engagement with the block at the lower end of the slot 76 therein. The other end of the Bowden wire is connected to one arm 86 of a pivoted lever 87. A second arm 90 of the lever 87 is adapted to be engaged by cam lugs 91 on a cam drum 92 forming a part of the pattern control mechanism of the machine.

When the pawl operating movement of the lever 45 is to be arrested, a cam lug 91 is moved into engagement with the arm W to turn lever 87 clockwise, as viewed in FIG. 6, to actuate the Bowden wire 78 and move the block 77 downwardly. At this time spring 85 tends to turn lever 67 counterclockwise from its inactive position of FIG. 6 to an active position in which the stud overlies and engages the upper surface of the arm 62 of the lever 45. However, when this action occurs at the time the roller 52 is in engagement with a low surface of the cam 55 between the high points 60 thereof movement of lever 67 is momentarily arrested by engagement of the stud with the end of arm 62. Thereafter, when lever 45 is turned clockwise by a high point 66 of the cam, the spring 85 acts to turn the lever 67 to its active position to arrest the action of the lever 45. When the cam lug 91 is moved out of engagement with the lever 87, as one or the other of the high points of the cam 55 is moved beneath the roller 52 spring 82 acts to move the Bowden wire 78 and block 77 to turnlever 67 clockwise to its inactive position to again permit the cam to operate the lever 45 and pawl 25 through tooth advancing movements.

Conventionally due to the limited number of available" butt levels on the jacks and other machine limitations the number of different design stitch patterns that may be formed in the dilferent portions of the stocking fabrics is limited to four and the butt pattern on the jacks for each of the patterns is arranged in a separate group of adjacent butt levels which are acted on by a corresponding group of selector levers and the latter are controlled by a butt pattern in a corresponding group of levels on the trick drum 21. Each of the different groups of selector levers is moved between active and inactive positions in the desired sequence by separate layout levers which are controlled and operated through Bowden wires from the cam drum 2 and, following each movement of any one of the groups of selector levers to active position, all of the selector levers of the group are always operated in the same manner by the associated butt pattern on the trick dnun 21 to form the same design stitch pattern. When it is desired to vary the design stitch pattern in one or other portions of the fabric and such variation may be formed by the same group of selector levers it is only necessary to change the butt pattern on the jacks or the operating butt pattern for the selector levers on the trick drum. However, when a variation in the design stitch patterns also requires a revision in the numbers of jack butt levels and selector levers, in addition to the changes to the jack butt pattern and butt pattern on the trick drum that are required to form the new design stitch patterns it is also necessary to provide new layout levers for activating and inactivating the revised groups of selector levers. In the mechanism shown herein only a single layout lever is provided to move all of the selector levers 29 to inactive positions when movement of the trick drum 21 is. arrested during reciprocating movement of the machine to form the heel, as hereinbefore set forth. The lever 95' is operated by a Bowden wire 94 by a pattern lever (not shown) controlled and operated in the usual manner by the cam drum.

In accordance with the instant invention each of the. selector levers 20 is adapted to be individually moved. between active and inactive positions in order to greatly increase the selectivity of the selector levers 26 in .selector levers of the groups are activated to form the design stitch patterns and at other times only selected ones of the levers of the groups are activated to form variations in the patterns in the same stocking fabric or in a plurality of stocking fabrics knitted in successive cycles of the machine. For this purpose, each selector lever 20 is provided with a second projecting nose portion 96 adapted to read a butt pattern formed at the same level on the tricks of a control drum 97. The drum 97, which is rotatably mounted on a shaft 98 secured in fixed position on the plate 31 (FIG. 4), is provided with a ratchet 100 adapted to be engaged and acted on by a pawl 101 pivotal-1y mounted on a rock lever 102 also pivoted on the shaft 98. A spring 105 connected between the pawl 101 and the plate 31 maintains the pawl in engagement [with the ratchet teeth. The lever 102 is rocked about the shaft 98 to operate the pawl 101 to advance the ratchet and control drum in one tooth steps by one arm 106 of a lever 107 pivoted on a stud 110 carried in a bracket 111 secured to the frame member 50 (FIGS. 6 and 7). A second arm: 112 of the lever 107 is connected by a link 115 to one arm 116 of a pattern lever 117 pivoted on a shaft or rod 118 on the frame member 50. A second arm 121 of the lever 117 is provided With a nose portion 122 for engagement with a row of cam lugs 123 on the cam drum 92. When a cam lug 123 is moved beneath the nose portion 122, lever 1 17 is turned clockwise, as viewed in FIG. 6, to operate pawl 101 to advance the control drum 97 one tooth of the ratchet 100. When the cam lug .is moved out of engagement with the nose portion, lever 117 is turned counterclockwise by a spring 124, connected between the arm 116 and the frame member 50, to reset the pawl 101 for its next advancing movement.

In addition to controlling the active and inactive positions of the selector levers 20, the control drum 97 is also adapted t move the pawl 25 into and out of engagement with the ratchet teeth 22 on the trick drum 21 to determine the time of operation of the trick drum. For this purpose there is provided a lever 125 pivoted on the pin 18 and having one arm 126 provided with a nose portion 127 adapted to read the butt pattern in one of the butt levels on the control drum 97. A second arm 130 of the lever 125 is provided with a nose portion 129 to read a butt pattern on the trick drum 21 for purposes hereinafter set forth. At its free end, arm 130 has a downwardly extending bent rod 131 having a lower portion for engagement with the pawl 25 (FIGS. 1 and A spring 132 connected between the arm 130 of the lever 125 and a pin- 135 carried on the plate 31 biases the lever 125 counterclockwise as viewed in FIGS. 1 and 2 to maintain the nose portions 127 and 129 in reading engagement with the associated butt patterns on the control drum 97 and trick drum 21, respectively. 7

When the machine is operating to knit plain fabric and no design stitch patterns are being formed, the nose portions 127 and 129 on the lever 125 are in engagement with tricks in the control drum 97 and trick drum 21, respectively, of which the butts have been removed and the lever is turned counterclockwise to the position of FIGS. 1 and 5 to maintain the pawl out of engagement with the ratchet teeth 22. When the trick drum 21 is to be rotated to control the operation of a group of the selector levers 20, a trick on the control drum 97 having a butt is moved beneath the nose portion 127 to turn lever 125 and pin 131 clockwise to again permit pawl 25 to engage the ratchet teeth 22. It is to be noted that the trick drum 21 is provided with only one trick in which the butt is removed at the level of the lever 125 and this trick also indicates the starting point for the butt patterns for operating the different groups of selector levers. When it occurs 6; that a trick on thecontrol drum 97 in which the butt is removed is moved beneath nose portion 127 to institute a pawl inactivatingmovement of the lever 125, the lever will be retained in its inactive position by the butts on the trick drum 21 thereby permitting continued operation of the pawl 25 to advance the trick drum until the trick on the trick drum without a butt is again moved beneath the nose portion 129 of the lever 125.

conventionally the cam drum92 is moved through one complete rotative cycle in steps or so -called moves, usually twenty-four to twenty-seven, during each stock-' ing knitting cycle. On the other hand the control drum 97, which is provided with forty-eight ratchet teeth 100, is only moved a suflicient number of steps or moves, for

instance twelve, each of which is instituted by a cam lug 91 on the cam drum 92 to activate and inactivate the trick drum 21 and the selector levers 20 in the desired sequence to form the different design stitch patterns in the different portions of the stockings. Hence, the control drum 97 is moved through a complete operatingcycle only during four complete stocking knitting cycles. Where the trick drum 21 and selector levers are to be operated in the same manner in successive stocking knitting cycles the same butt pattern on the control drum 97 is merely repeated in each twelve tooth segment of the control drum. However, where a variation in the design stitch pattern in the different portions of successive stockings is desired, the operating sequence of the selector levers may be varied in the different segments of the control d-rurn. For instance in a leg portion in which a 3 x 1 pattern of tuck stitches is to be formed, a group of eight selector levers are normally simultaneously activated to follow the butt pattern on the .trick drum 21. The butt pattern in one segment of the control drum may be set up to activate the eight selector levers to produce the normal 3 x 1 pattern of tuck stitches throughout the leg portion of one stocking. The butt pattern in the other segments of the control may be set up to activate only certain ones of the eight selector levers to vary the normal 3 x 1 pattern in spaced portions of the leg pattern or throughout the leg pattern in each of the other three stockings. Also, similar variations of the design pattern in the afterwelt portion of the stockings could be made by activating all or only certain ones of the group of selector levers normally allotted to the formation of the design pattern in this portion of the stocking.

As a further example of the capabilities of the mechanism of the inst-ant invention, FIG. 8 illustrates a butt pattern on the jacks arranged in four different groups of levels 140, 141, 142 and 143. Groups 140, 141 and 142 are arranged to select the needles to form 3 x 1, 1 x 1 and 2 x 1 micro-mesh patterns, respectively, and group 143 is arranged to form a pattern of lace stitches. 'l he butt pattern in each of the different segments of the control drum 97 could then be arranged to control the selector levers associated with the different groups of jack butts in a different manner in the successive stocking knittng cycles of the machine. For instance one segment of the control drum would act to control the selector levers associated with group to form a 3 x 1 micro-mesh pattern in the leg of one stocking, and the next segment of control drum would act to control the selector levers associated with group 141 to form a 1 x 1 micro-mesh pattern in the leg of the next stocking, etc.

lit will be obvious from the foregoing that the mechanism of the instant invention provides the means for individually controlling the operation of jack selecting levers which not only permits the formation of a greater number of design stitch patterns in the stocking fabrics but which also permits the formation of variations of such design stitch patterns in successive stocking fabrics knitted in a plurality of successive knitting cycles of the machine. Furthermore, it is obvious that the mechanism. is applicable to both singleand multiieed machinesd When the mechanism is provided at each knitting sta-- tion of a multifeed machine additonal variations of the, same design stitch pattern may be made in the same stocking. For instance where the mechanism at one Station operates a group of selector levers in one manner:

to form one variations of the 3 x 1 pattern in the leg of the stocking, the mechanism at the other station may be adapted to operate the same group of selector levers in; another manner to form a further variation of the 3 x 1, pattern in another part of the stocking.

It will be understood that the improvements specifically shown and described by which the above results are b 5 tained can be changed and modified in the various ways: without departing from the invention disclosed and heremoving said selector levers between active positions in;

which said selector levers are operated by said trick drum and inactive positions, and pattern means for intermittently operating said control drum.

2. In a circular knitting machine for knitting tubular stocking fabrics having a rotatable cylinder, needles in said cylinder, a pattern drum adapted to be operated. through one complete rotative cycle to operate the machine during the knitting of each complete stocking, pattern jacks associated with said needles and pattern means for acting on a butt pattern on said pattern jacks to selec tively operate said needles to form design stitch patterns in said stockings, said pattern means comprising selector levers, a trick drum having a trick butt pattern for selectively operating said selector levers, means for operating: said trick drum, a control drum for individually controlling the movement of said selector levers between inactive positions and active position-s in which said selector levers are operated by said trick drum to act on the: butt pattern of said jacks, and means for operating said control drum.

3. Ina machine according to claim 2 in which said control drum is operated by said operating means through a partial rotation during a first rotative cycle of said pattern levers between said activeand inactive positions and at least a second partial rotation during a second rotative cycle of said pattern drum.

4. In a machine according to claim 2 in which said control drum is provided with a controlling pattern for moving said selector levers between active andinactive positions and said controlling pattern is divided into a first portion for controlling the movement of said selector levers between said active and inactive positions and at least a second portion for controlling the movement of said selector levers between said active and inactive positions in a different order than said first portion.

5. In a machine according to claim 4 in which said control drum is operated by said operating means through said first and second portions of said controlling pattern during first and second rotative cycles of said pattern drum.

6. In a machine according to claim 4 in which said controlling pattern on said control drum is divided into a plurality of different portions each of which is adapted to move said selector levers between active and inactive positions in a dilferent order than the others of said different portions, and said control drum is operated through each of said different portions by said operating means in dilierent rotative cycles of said pattern drum.

7. In a circular knitting machine for knitting tubular stocking fabrics and adapted for rotary operation to knit run-down portions of said stocking fabrics and for reciprocatory operation to knit heel and toe portions of said stocking fabrics, said machine having a rotatable cylinder, needles in said cylinder, and a pattern drum adapted to be operated through one complete rotative cycle to control the operation of said machine during the knitting of each complete stocking fabric, in combination with means for selectively controlling the operation of said needles to form design stitch patterns in said run-down portions of said stockings including pattern jacks associated with said needles, pattern butts on said pattern jacks, selector levers for acting on said pattern butts, a trick drum having a trick butt pattern for selectively operating said selector levers, means for operating said trick drum, a control member for individually controlling the movement of said selector levers between inactive positions and active positions in which said selector levers are operated by said trick drum to act on said pattern butts on said jacks, and means for operating said control member through a complete operating cycle during a plurality of rotative cycles of said pattern drum.

8. In a circular knitting machine having a rotatable cylinder, needles in said cylinder adapted to be operated to knit yarns fed thereto into tubular stocking fabrics, a pattern drum adapted to be operated through a complete rotative cycle to control the operation of said machine during the knitting of each stocking fabrics, and pattern means for selectively operating said needles to form different design stitch patterns in said stocking fabrics including jacks associated with said needles, pattern butts on said jacks at a plurality of different levels, said pattern butts being arranged in diiferent groups of levels each of which is adapted to select said needles to form a different one of said different design stitch patterns, a group of selector levers associated with and corresponding in number to the pattern butt levels in each of said different groups, a trick drum having a trick butt pattern for selectively operating said selector levers in each of said groups, means for operating said trick drum, a control member for individually controlling the movements of said selec tor levers in each of said groups between inactive positions and active positions in which said selector levers are operated to act on the pattern butts on said jacks in the group of levels associated therewith, and means for operating said control member through a complete operating cycle during a plurality of rotative cycles of said pattern drum.

9. A pattern mechanism for a circular knitting machine adapted to knit tubular stocking fabrics, said pattern mechanism including a first patterning means which is operated through a complete operating cycle during the knitting of each stocking fabric, a second patterning means, means for operating said second patterning means through at least two complete operating cycles during each complete operating cycle of said first patterning means, a third patterning means, and means for operating said third patterning means through a complete operating cycle during at least two complete operating cycles of said first patterning means.

References Cited by the Examiner UNITED STATES PATENTS 2,694,908 11/1954 Lawson 66-50 ROBERT R. MACKEY, Acting Primary Examiner. RUSSELL C. MADER, Examiner. 

1. IN A CIRCULAR KNITTING MACHINE HAVING A ROTATABLE CYLINDER, SLOTS IN SAID CYLINDER FOR SLIDABLY MOUNTING A CIRCULAR SERIES OF NEEDLES, PATTERN JACKS IN SAID SLOTS FOR SELECTIVELY OPERATING SAID NEEDLES, AND PATTERN MEANS FOR ACTING ON A BUTT PATTERN ON SAID PATTERN JACKS COMPRISING SELECTOR LEVERS, A TRICK DRUM HAVING A TRICK BUTT PATTERN FOR SELECTIVELY OPERATING SAID SELECTOR LEVERS, MEANS FOR OPERATING SAID TRICK DRUM, A CONTROL DRUM FOR INDIVIDUALLY MOVING SAID SELECTOR LEVERS BETWEEN ACTIVE POSITIONS IN WHICH SAID SELECTOR LEVERS ARE OPERATED BY SAID TRICK DRUM AND INACTIVE POSITIONS, AND PATTERN MEANS FOR INTERMITTENTLY OPERATING SAID CONTROL DRUM. 